Ismael admitted the ferocity of the support took some getting used to in the first half of the 1-0 defeat, but he thinks his side wll now be much better prepared for the second leg at Swansea City on Tuesday.
Coronavirus restrictions meant there were only round 4,500 fans in the ground for Monday's Championship play-off semi-final first leg but 436 days after the gates were last opened to supporters, they more than made up for it.
Ismael had a brief spell as a Crystal Palace centre-back in the mid-1990s, but Monday's atmosphere was on a completely different level.
"It was an incredible thing," said Ismael, who took over as Reds manager in October.
"Even though I dreamed about this it was incredible, the emotion, the passion, the emotional connection.
"This is exactly why we love football and it was simply a great feeling."
There were on Swansea fans in the ground on Monday, just as there will be no Barnsley supporters at the Liberty Stadium for the return leg.
Although the situation will not be as new to the Swans as it was to the Reds on Monday, the dynamic will still change, and the pressure on a side whose budget - never mind their first-leg advantage - means they are expected to progress to the final rather than hoping to as Barnsley are will be great.
"It was a new situation for the players and we are all human beings. It was a normal reaction," said Ismael, whose side grew into the game after the first 20 minutes and hit the crossbar in stoppage time at the end of the game.
"The atmosphere in the stadium was incredible and I can understand it took us a while to get used to the emotion but we dealt with it perfectly in the second half.
"It's much for the players to know now that on Saturday there's only one way, we have to score goals and put the pressure on Swansea.
"Maybe it's better for us now to have that focus.
"It's been a long season but we need to make a big effort."
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